Australian scientists have developed a non-invasive method of diagnosing sleep apnoea.

The technology could replace the current method of diagnosing the disorder, which is expensive and time-consuming.

Biomedical engineer and co-researcher Dr Udantha Abeyratne, of the University of Queensland, says obstructive sleep apnoea (OSA) is a sleep disorder that causes a narrowing of the airways, which can lead to temporary cessation of breathing.

He says approximately one-quarter of middle-aged men suffer OSA.

At present the only way to diagnose a person with OSA is to have them spend a night at a sleep centre or hospital, hooked up to a machine that monitors their sleep continuously.

"There are very long waiting lists to come into the hospital and get tested," says Abeyratne.

As a solution to the problem Abeyratne and his colleagues invented a non-contact method of screening patients suspected of OSA, which could eventually be used at home.

Abeyratne says the device records the sounds of a person's snoring, which "is a very early symptom of sleep apnoea."

By monitoring the changes in pitch, frequency and other characteristics of the snores, the researchers are able to tell who is at risk of developing OSA.

"Snoring carries information about airway obstructions," he says.

Screening tool

Abeyratne warns that the sound recordings can't be used to diagnose OSA, and people will still need to spend a night in a sleep laboratory for a full diagnosis.

But he says the technology will act as a valuable screening tool for the wider population.